LDAP filter

Hi all you AD/LDAP experts. I have a question or two for you this evening.

My filter looks like OU=Global,DC=Corp,DC=One,DC=Co

On top of that I have 6 LDAP OU defintions that each have a different RDN (which is OU=).

My question is (since I didn't set this up), if I have 6 OU definitions with unique RDN filters on the OU, there's no chance the filter will pick up anything outside of these definitions, right? I ask because it seems like we may be pulling from a directory we want to disclude. Is there a way to specifically uninclude a particular OU? Or are all the definitions critera TO include something (as opposed to a definition that excludes one)?

One last question.

If I have a filter that's just OU=Global,DC=Corp,DC=One,DC=Co. On this domain we have one OU definition which does NOT have an RDN. The only thing it has is the generic filter of (&(objectClass=person)(sn=*)(sAMAccountName=*)(!(objectClass=computer))). Does that mean this will include/search EVERY directory and subdirectory starting at the Global OU?

I appreciate all the help. I can't find answers to these questions on the wiki.